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26 Cards in this Set
- Front
- Back
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What are 2 reasons Prist is added to the fuel that is used in a turbojet aircraft? |
Prist is a biocidal agent that (1) kills the scum-forming bacteria in the fuel tank and, (2) acts as an antifreeze agent, lowering the freezing point of the entrained water that is released from the fuel. |
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What are 2 types of fuel cells that are used in modern aircraft? |
Integral fuel cells (cells that are a sealed-off portion of the structure) and bladder type cells. |
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Why are fuel tanks separated into compartments or have baffles installed in them? |
The compartments or baffles keep the fuel from surging back and forth as the aircraft changes its attitude in flight. |
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What is meant by an integral fuel cell? |
A part of the structure in which all of the seams and joints are sealed so they will be fuel tight. The structure itself then becomes the fuel tank. |
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What are fuel system strainers located? |
One strainer is located in the outlet to the tank, and the main strainer is located in the fuel line between the outlet of the fuel tank and the inlet to the fuel metering device. |
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What are 3 uses of a centrifugal booster pump that is installed in an aircraft fuel tank? |
Booster pumps are used to produce fuel pressure for starting the engine, to keep the fuel vapor locking at high altitude, and to transfer fuel from one tank to another. |
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What is meant by a compensated engine-driven fuel pump? |
And engine-driven fuel pump whose pressure relief valve is acted upon by the pressure of the atmosphere. A compensated pump varies its outlet fuel pressure so it will stay a constant amount higher than the pressure of the air that is entering the carburetor. |
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Why do engine driven fuel pumps have a bypass valve in them? |
The bypass valve allows fuel from the booster pump to flow around the engine-driven pump mechanism for starting the engine and to supply the engine with fuel if the engine-driven pump should fail. |
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Why must an aircraft fuel valve have a detent in its operating mechanism? |
The detent gives the pilot a positive indication by feel when the selector valve is in the full ON and full OFF position. |
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What characteristic of the fuel is measured with the mass-flow fuel flowmeter that is used with turbine engine aircraft? |
The density of the fuel. |
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What is used as a flowmeter for a fuel-injected, horizontally opposed aircraft engine? |
A pressure gauge that measures the pressure drop across the injector nozzle in the engine. |
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What is meant by a cross-feed system in an aircraft fuel system? |
A cross-feed system allows fuel from any tank to flow to any engine. |
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Why do some aircraft have provisions for jettisoning fuel in flight? |
Aircraft that are certificated with a higher takeoff weight than their allowable landing weight must have provisions for jettisoning fuel. This allows enough fuel to be dumped to bring the weight down to that allowed for landing in case an emergency occurs before this amount of fuel can be burned off. |
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What must be done to a welding fuel tank before it can be repaired by welding? |
All of the fuel vapors must be purged by flowing live steam through the tank, by soaking it in boiling water, or by chemically neutralizing the fumes. |
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What safety precautions must be taken before a person enters the fuel cell of a large aircraft? |
The cell my be thoroughly purged of all fumes, the person entering the cell must wear proper safety equipment, and there must be a person standing by on the outside of the cell. |
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What is meant by a single-point fueling system? |
A pressure fueling system in which the fuel is pumped into the aircraft through an underwing fueling port. The fuel flows into a manifold, and then into the correct fuel tank selected at the fueling station. |
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What gas is used to purge fuel tanks of all fuel vapors? |
Carbon dioxide or nitrogen. |
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Why do turbojet aircraft normally have fuel temperature indicators? |
Because of the low temperatures at which these aircraft operate, it is possible for water participate out of the fuel and freeze on the filters, shutting off fuel to the engines. The temperature can be kept above freezing by directing it through a fuel heater as is needed. |
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How is a fuel leak indicated on a reciprocating engine powered aircraft? |
The dye in the gasoline stains the area around the leak. |
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What is the purpose of a drip gauge in the fuel tank of a large aircraft? |
The drip gauge allows a mechanic to check the fuel level in a tank from the bottom of the tank. |
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What safety precautions should be taken before am aircraft is defueled? |
Be sure that the fuel truck is properly located, the truck and the aircraft are electrically grounded, all electrical power except that needed for the defueling operation is turned off, and the fuel is returned to the proper truck or other container. |
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What markings must appear near the filler opening of the fuel tanks on reciprocating engine powered aircraft, and on a turbine powered aircraft? |
On a reciprocating engine powered aircraft: the word FUEL and the minimum grade of fuel. On a turbine engine powered aircraft: the word FUEL, the permissible fuel designations, the max permissible fueling supply pressure, and the maximum permissible defueling pressure. |
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Other than reducing weight, what other function can be accomplished with a fuel jettisoning system? |
Fuel can be dumped from the heavy wing in order to maintain lateral stability; a fuel dump system is required for all transport airplanes if the maximum takeoff weight is more than 105% of the maximum landing weight. The airplane must be free of fire hazards during dumping, and fuel must dump free and clear of the airplane. |
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How is the weight of a bladder type fuel cell supported? |
The bladder type cell depends on the structure of the cavity in which it sits to support the weight of the fuel within it. They are made of either rubber or nylon. |
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What are the advantages of a single point pressure fueling system? |
Pressure fueling, sometimes referred to as single point or underwing fueling, and greatly reduces the time required to service large aircraft. It eliminates aircraft skin damage from hoses and hose nozzles, and reduces the changes of fuel contamination. |
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Which type fuel quantity gauge is considered to be more accurate than the other types? |
The electronic capacitance type, because it measures by weight instead of gallons. |
